Tag Archives: sleep

Jeff Iliff is a neuroscientist at Oregon Health & Science University, previously doing research into brain cleansing mechanisms at University of Rochester Medical Centre.

Summary

We spend roughly a third of our lives asleep, but it is not clear why the body needs it. 2,000 years ago it was proposed by Galen that the brain sent fluids around the body, and these were returned during sleep to rejuvenate the brain. The idea is ludicrous today, but Jeff still suggests brain activity could account for our need of sleep. The brain uses 25% of our energy but takes only 2% of our mass. The first major issue in any body organ is nutrient intake – which is satisfied by the circulatory system and the network of blood vessels surrounding the brain. The second issue is waste disposal, which in most organs is done through the lymphatic system. The lymphatic system transports waste from the cells to bloodstream, however it does not exist in our heads so cannot be used by the brain. So how does the brain dispose of waste? This was where Jeff started tackling the problem.

The brain is surrounded by cerebral spinal fluid (CSF). Waste is dumped into CSF, which is then transported to the blood. To help this, CSF is pumped along the outside of blood vessels – to clean and penetrate deeper into the brain wherever blood vessels are. However, this action only happens while we sleep. As we sleep the brain cells contract, to open up spaces between them and let the CSF flow more easily. Ironically, this idea of fluid rushing through the brain is similar to Galen’s ideas thousands of years ago.

What sorts of wastes need to be cleaned? One is Amyloid Beta – which is made all the time, but an inability to clear them away is thought to be a factor in getting Alzheimers disease. Studies have found that a decrease in sleep is associated with an increase in Amyloid Beta in the brain.

While we sleep, our brain never rests. It is busily cleaning this important machine, and possibly preventing serious issues later. By understanding these housekeeping functions today, we may be able to prevent serious diseases of the mind tomorrow.

My Thoughts

Interesting talk and interesting research. I learnt a bit about brain activity, sleep and Alzheimers all at once. He summed up a lot in less than 12 minutes.

Sleep is the single most important behavioral experience we have. But the perception and role of sleep in our society has shifted from importance to a waste of precious time. Shakespeare referred to sleep as “nature’s soft nurse”, but Edison thought it was a “heritage from our cave days.” People often feel similarly to the latter, but it’s usually because they don’t understand the purpose of sleep.

The reality is that our brain doesn’t shut down during sleep. The most popular theory for why we sleep is that sleep controls our brain function. Sleep deprivation is shown to cause poor memory, increased impulsiveness, and poor creativity. But that’s not even the worst part. Sleep is strongly connected to serious health problems like cardiovascular disease and mental illnesses. Sleep deprivation can cause a 50% higher rate of obesity, brought about by excess release of the hormone, ghrelin, which triggers your hunger. Sustained stress, another result of sleep deprivation, suppresses your immune system.

Foster spends the second half of his talk on the genetic ties between sleep disruption and schizophrenia. A discovery was made that stabilizing sleep also helped reduce symptoms of paranoia. From all the different examples and study’s he cites you can draw 3 conclusions.

Sleep and mental illness are tied together

Sleep disruption can be used as an early warning signal for illnesses

Sleep centers are a new therapeutic target for solving other problems

The question you might be wondering now is, how do I know if I’m getting enough sleep?

If you need an alarm clock to wake up, are grumpy and irritable, or need a cup of coffee to do anything: you are probably sleep deprived. The key is to listen to your body. You might need 6 hours of sleep or you might need 10 hours. There is actually no correlation between waking up early and having better health (or more wealth). To get a good nights sleep, make sure that you’re room is as dark as possible and slightly cool. Reducing light exposure/electronics use during the 30 minutes prior will also help.